"Although the following essay may seem, at first view, to propose nothing to itself but to amuse the public with a philosophical speculation; yet as its object is to establish the unity of the human species, by tracing its varieties to their natural causes, it has an obvious and intimate relation with religion, by bringing in science to confirm the verity of the Mosaic history. It has lately become a kind of cant with certain superficial smatterers in physical science to speak of revealed religion, and of the spirit of piety as being hostile to profound researches into nature, lest they should be found to contradict the dogmas of revelation. We see these men, likewise, with equal ignorance and vanity, contemptuously insinuate that the friends of piety are always ready to rest their opinions, not on well ascertained facts, but on the supposed authority of Heaven, to save them the pains, and the hazard of enquiries so dangerous to contented superstition. These self-dubbed naturalists, vain of their own faint shadow of knowledge, because they know so little, seem to have forgotten the existence of such men as Newton, or Boyle, Bacon or Mede, and a thousand others, equally distinguished for the depth of their enquiries into the mysteries of nature, and for their sublime and fervent piety towards its Author. Genuine philosophy has ever been found the friend of true religion. They are only spurious pretences to science which have wantonly arrayed themselves against the holy scriptures. In a question of that nature which is discussed in the following essay, I would be far from introducing the authority of religion to silence enquiry, and equally far would I be from making it a substitute for proof. I appeal to the evidence of facts, and to conclusions resulting from these facts which I trust every genuine disciple of nature will acknowledge to be legitimately drawn from her own fountain. From Natural Science, which has been cultivated with more than common ardor and success in the present age, she now forms her chief attacks against the doctrines, and the history of religion. And on this quarter she has pressed them with the greatest zeal. While others, therefore, are successfully defending the interior fortresses of religion, and extending her practical sway over the hearts of men, I thought that I might render a valuable service to the cause, by cooperating, in some degree, with those who are defending her outworks, and carrying their attacks into the enemy's camp"--Introduction. (PsycINFO Database Record (c) 2008 APA, all rights reserved).